Fishers Island (or in Pequot "Munatawkit") is a 4-square mile island just two miles off the coast of Connecticut and Rhode Island. It is part of New York State even though its zip code and central telephone exchange correspond to Connecticut.
Like the rest of Suffolk County, Fishers Island was originally part of the Colony of Connecticut when Connecticut was founded in 1640. However, when the Duke of York received his land grants in 1664 and founded New York, the language of the grant included "all islands" in the area. Since the Duke of York was the son of a king (Charles I) and the brother of a king (Charles II) and would eventually be King (James II), his claims took precedence over Connecticut's. It also did not help Connecticut's case that the assassins of Charles I were given asylum in Connecticut.
The land grant actually also included Block Island, the coastal islands of Providence Plantations (R.I.), Martha's Vineyard, and Nantucket. The Duke of York sold these off or traded them for favors, but kept Fishers Island and Suffolk County out of spite.
Fishers Island has a population of about 300. In the 19th Century, a brickworks was maintained there using the clay that makes up most of the island's substratum.